Often it is necessary to test launch package elements such as projectiles or shells for quality or for design effectiveness. One common method of testing launch package elements is to fire them under standardized conditions. Similarly, armor can be tested by firing projectiles at it under standardized conditions and then examining the armor for type and extent of damage. In either case, variance of the launch package element's location in the gun breech can cause error in test results. Since launch package elements are normally squeezed in the cylindrical cavity of the breech, a certain degree of force is needed to axially reposition them within the cavity. This force, typically applied by tapping the package element, often moves the element too far, whence it is necessary to repeat the repositioning until the desired accuracy is achieved. If the launch package has a sabot and penetrator, the tapping can bounce the penetrator away from the sabot, so that the sabot slams against the penetrator upon firing the launch package, possibly damaging the package, harming the gun, and affecting test accuracy.
The difficulty of properly seating a projectile is greater when placing the launch package in a rifled test gun. The launch package must be shoved into the breech forcefully enough to engrave the package with the rifling of the gun barrel, but must be very accurately placed to achieve consistency in test conditions. Failure to advance the package into sufficient engravement with the gun barrel may cause the launch package to Jam in the gun breech when the test gun is fired. Jamming occurs during firing if the launch package propellant's pressure does not overcome the package's initial engravement force and static friction with the gun breech or barrel. If the launch package is not engraved at all with the rifling during seating, the package may skew out of concentricity with the gun barrel as it first contacts the rifling grooves upon firing, thereby introducing error into the test results.
Our launch element seater is a device that improves the efficiency and accuracy with which a launch package element can be placed within a breech. The invention includes a tube having a seat member at one end for pushing a launch package element part of the desired axial distance into the cylindrical cavity of a breech. The head pushes the element until a breech plate on the tube abuts the breech, whereby the tube is precisely located relative to the breech. While the tube is so located, a human operator turns a threaded rod extending from the tube and connected to the head. The rod advances the head from the tube slowly, without jerking, to accurately push the launch package element to a desired position. Our seater also includes means to detect when advancement of the seat member from the tube is at the desired distance and to prevent subsequent advancement of the seat member.